SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6569ce9a7752ffbb855111a9fb5b53c3c29851011a9be89f7fc62289e92ba336' 
  AND token = 'ygQWjGI3RiTyRBceIsWp2hIjmkOWeH0X6s8MFbbotqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}